Abstract: An engine in which the cylinders are each provided with a first intake valve, a second intake valve and an intake passage common to the first and second intake valves. The intake passage is divided into a central passage and two side passages located on each side of the central passage by two side separating walls, which extend from the valve stem guides of the first and second intake valves toward the upstream of the intake passage. The downstream end portion of the central passage is divided into two branch passages. Each of the branch passages is in communication with the corresponding side passage via an opening formed in the corresponding side separating wall. A fuel injector is arranged in the central passage, and a control valve is arranged in the central passage upstream of the fuel injector and opens when the engine is operating under a heavy load.